Today flight accident investigations largely rely on the data recorded in the so-called flight recorder. Flight recorders used onboard commercial aircraft are usually fixed to the aircraft. Thus, if access to the aircraft itself is difficult, for example, because the aircraft accident occurred over open water and the wreckage sunk after the accident, it may be difficult to retrieve the flight recorder. To overcome this disadvantage, it has been suggested to transmit at least part of the data stored in the flight recorder from an aircraft to a receiver, e.g., a ground station before the accident happens such that at least some information is readily available well before the flight recorder has been successfully retrieved.